Twist-open firearm



Sept. 4, 1962 E. s. VARTANIAN TWIST-OPEN FIREARM 3 Sheets-Sheet 1 Filed March 1, 1961 INVENTOR. EDWIN S. VARTANIAN Sept. 4, 1962 E. s. VARTANIAN TWIST-OPEN FIREARM Filed March 1 1961 3 Sheets-Sheet 2 JNVENTOR. EDWIN S. VARTANIAN Sept. 4, 1962 E. s. VARTANIAN 3,052,053

TWIST-OPEN FIREARM Filed March 1 1961 3 Sheets-Sheet 3 INVENTOR. 54 EDWIN S,VARTAN\AN United States Patent C) 3,052,053 TWIST-OPEN FIREARM Edwin S. Vartanian, North Haven, Conn., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Mar. 1, 1961, Ser. No. 92,531 4 Claims. (CI. 4213) The present invention relates to firearms and relates in particular to a twist-open shotgun or to a twist-open rifle.

A particular feature of the invention is the provision of a novel, inexpensive firearm.

A further feature of the invention is the provision of a shotgun or a rifle having, basically, two main elements, namely, a butt stock which includes a trigger group and a locking block and a separable bar-rel including a barrel block.

A further feature of the invention is that there is provided a shotgun or a rifle whose construction and arrangement eliminates a receiver element.

A still further feature of the invention is the provision of a shotgun or a rifle having a novel forearm.

A twist-open firearm embracing certain features of the present invention may comprise a butt stock, a locking block secured to the butt stock and a barrel including a barrel block, said barrel being detachably connected to the butt stock through the barrel block and the locking block, said barrel being rotatable relative to the butt stock about an axis generally parallel to the barrel axis, a removable forearm carried by the barrel and pin means rigidly fixed to the locking block and cooperating with the barrel block to connect the barrel to the butt stock and to lock the forearm to the barrel.

Other features and advantages of the present invention will become more apparent from an examination of the succeeding specification and claims when read in conjunction with the appended drawings in which:

FIG. 1 is a perspective view of a twist-open shotgun embracing the principles of the present invention;

FIG. 2 is an illustration similar to FIG. 1 showing the barrel rotated to a loading and/or ejection position;

FIG. 3 is a vertical section of a portion of the illustration of FIG. 1 as viewed in the plane of the lines 33;

FIG. 4 is a perspective view of the forearm;

FIG. 5 is a perspective view of the locking block;

FIG. 6 shows the relative position of the barrel and butt stock just prior to the ejection of a spent shell, and

FIG. 7 shows the barrel fully rotated relative to the butt stock to the open position ready for loading.

Referring now to the drawings, note that the basic elements of the shotgun comprise a barrel 10 and a butt stock 11 hinged together by means of a lock carrying a pin 17 received in a barrel block 18 so that the barrel may be rotated relative to the butt stock about an axis yy (which is generally parallel to the longitudinal axis of the barrel from a closed position as shown in FIG. 1 to an open position indicated in FIG. 2).

The butt stock 11 carries a trigger assembly, indicated generally by the reference numeral 12.

Since the trigger assembly forms no part of the present invention, it is not deemed necessary to describe this portion of the firearm in detail except to state that the reference numeral 13 designates manually operated cocking lever while 14 designates a firing pin and the reference numeral 16 denotes the trigger.

The barrel 10 is hinged to the butt stock 11 by means of a hinge pin 17 rigidly fixed to locking block 15 in turn fastened to the butt stock 11 by any suitable means.

'In the present embodiment of the invention, the locking block 15 is connected to the butt stock 11 by means of 3,052,053 Patented Sept. 4, 1962 ice screws introduced into the mounting holes 19--19 as is most apparent in FIG. 5.

The barrel block 18 receives the barrel 10 in a pressed fit and is formed with a bore 21 which makes a sliding fit with the hinge pin 17. Thus, the barrel is rotatable relative to the butt stock about the hinge pin as previously described and, in addition, it is possible to separate the barrel 10 from the butt stock 11 by grasping the barrel in one hand and the stock in the other. Upon exerting a tensile stress, split 'O-ring 22 is depressed into a groove formed in the pin 17 in well known fashion and the barrel 10 and the barrel block 18 slide off the pin 17 as a unit.

A plastic forearm 20 is carried by the barrel and held locked to the barrel by special cooperation with the hinge pin 17, as will be described in detail hereinafter.

The forearm is of plastic material and by virtue of its generally U-shaped structure and relatively thin sidewalls has a property of resilience.

Taking advantage of this resilience, the wings 23 and 24 are shaped generally in the conformation of the barrel in the region indicated by the reference numeral 25 (.FIG. 1) so that this portion of the forearm is snapped around the barrel suitably separating the wings 23 and 24 with the result that the forward portion of the forearm is retained frictionally.

The rear end of the forearm is formed with a plastic bridge element 26 molded integrally with the body of the forearm and is further characterized by an arcuate saddle 27 operative to engage and snugly contact an undercut 28 formed in the barrel 10.

The bottom of the bridge 26 is formed with an arcuate cut-out 29 corresponding to the radius of the right end 31 of the hinge pin 17 so that when the barrel 10 carrying the forearm is assembled to the butt stock 11 by sliding the barrel block 18 relative to the butt stock with the bore 21 receiving the pin 17, the right end 31 of the pin 17 engages the cut-out 29 to hold the bridge 26 snugly into interlocking engagement with the undercut 28 formed in the barrel.

Obviously, the interference between the shoulder 33 on the barrel and the bridge 26 prevents the forearm 22 from sliding axially relative to the barrel.

The bore .21 formed in the barrel block receives pin 17, as previously described, and upon seating the barrel block 118 on the pin 17 to the position shown in FIG. 3, O-ring 22 is free to snap outwardly against a chamfer 30 formed in the barrel block operative to retain the barrel 10 and the butt stock 11 against relative axial motion but the members are free to rotate about the pin.

The barrel block 18 is formed with a cut-out portion indicated generally by the reference numeral 36 and is utilized to house an ejector lock assembly comprising a combined ejector-lock pin 3-7 urged constantly to the left, as viewed in FIG. 3, by a coil spring 38 seated on the right in a recess 39 formed in the plastic bridge member 3-6 and urged upwardly by a leaf spring 42.

The ejector-lock pin 37 is obviously free to reciprocate axially and is free to move upwardly and downwardly as will be described in more detail hereinafter.

With the firearm in the closed position, mating undercuts formed in the locking block 15 and the barrel 10 interlock with one another, as shown at 43 (FIG. 3), while a shoulder or cam follower 44 of the ejector-lock pin 37 engages a notch 46 (FIG. 5) formed in the locking block to retain the barrel and the butt stock in the closed position.

Thus, to open the firearm, it is merely necessary to twist the barrel 10 relative to the butt stock 11 in the direction shown in "FIGS. 6 and 7 with the result that the ejector-lock pin 37 is cammed to the right by the protuberance adjacent the notch 46 against the coil spring 38.

This relieves the interference between the follower 44 and the notch 46 and the barrel is freely rotated from the position shown in FIG. 1 to the position shown in FIG. 2.

Upon this occurrence, the follower 44 traverses cam track 47 allowing the ejector lock pin to move to the left as viewed in FIGS. 3 and 7. When the barrel has been rotated clear of the locking block 15 or to the position shown in FIG. 6, ejector lug 48 nested behind the rim of a shotshell 49, as is apparent in FIG. 3, is operative to cast a spent shell out of the chamber of the barrel 10.

During the course of the traverse of the ejector-look pin 37 to the left, as viewed in FIGS. 3 and 6 in ejecting a spent shell, lug 52 encounters a chamfer 53 on the barrel 10 and the interference developed between these two surfaces is operative to drive the left end of the member 37 downwardly against the action of leaf spring 42 so that lug 48 is dropped downwardly clear of the chamber and so as not to interfere with loading.

A reference to FIG. 7 shows the lug 48 cast downwardly by the action just described and new shell 54 may be readily introduced without interference.

After the introduction of a new shell into the chamber, the barrel 10 is rotated relative to the butt stock 11 and follower 44 begins to traverse cam track 47 in a reverse direction with the result that the pin 37 is driven to the right as viewed in FIG. 3.

As soon as the lug 52 drops oif the surface 56 and rides down the chamfer 53 in response to urging of spring 42, the ejector lug effectively moves to the right and upwardly as viewed in FIGS. 3 and 7 to a position forward of the rim of a shotshell so as to be conditioned for subsequent ejection.

The primary advantages of the disclosed embodiment of the invention are as follows: (1) The pin 37 serves as a combined ejector and lock. (2) The forearm 22, by virtue of its bridge structure, cooperates with the barrel hinge pin 17 to lock the forearm to the barrel. (3) The barrel 10 is readily separable from the butt stock 11.

It is anticipated that a variety of modifications and design changes may be devised in the disclosed embodiment of the invention without departing from the spirit and scope of the invention.

What is claimed is:

1. A twist-open firearm comprising two main assemblies characterized by a composite butt stock assembly and a separable barrel assembly including a chamber, said first assembly being fitted with pin means operative to receive and support the barrel assembly whereby the barrel is rotatable relative to the butt stock assembly to expose the chamber, a removable forearm operative to engage the barrel assembly frictionally at its forward end and having a bridge member at its rear end cooperating with the pin means and the barrel assembly whereby the forearm is held fixed when the butt stock assembly and barrel assembly are operatively connected, a combined ejector and look means carried by the barrel assembly and cooperating with said butt stock assembly effective to eject a spent cartridge when the barrel assembly is rotated to an open position relative to the butt stock assembly and operative to engage and lock the butt stock assembly to the barrel assembly when said assemblies are in a firing position.

2. The firearm of claim l above wherein the butt stock carries a locking block formed with a cam surface and the combined ejector and lock means is formed with a cam follower which engages and cooperates with said cam surface.

3. A twist-open firearm comprising a butt stock and a barrel assembly including a barrel, said barrel assembly being detachably connected to the butt stock and being rotatable relative to the butt stock about an axis generally parallel to the barrel axis, a removable forearm carried by the barrel, hinge means rigidly fixed to the butt stock and operative to connect the barrel assembly to the butt stock and to lock the forearm to the barrel and a combined ejector and lock means carried by the barrel assembly operative to lock the butt stock to the barrel assembly.

4. The device of claim 3 wherein the hinge means comprises a pin rigidly fixed to the butt stock and a barrel block rigidly fixed to the barrel.

References Cited in the file of this patent UNITED STATES PATENTS 209,925 Rupertus Nov. 12, 1878 548,075 Lundgren et al. Oct. 15, 1895 801,295 Zeise Oct. 10, 1905 2,447,229 Bradley Aug. 17, 1948 

